Hello Geoffrey,

Thanks for reaching out to Ask Extension about herbicides and spurge in your lawn.

While we can't make specific product recommendations, you will want to find an herbicide with the following  active ingredients or mix of ingredients: 2,4-D, and MCPP (mecoprop), and dicamba. Make sure the product you choose lists spurge on the label.

Here is more information about broadleaf weeds in lawns and how to manage them:

https://planttalk.colostate.edu/topics/lawns/1525-controlling-broadleaf-weeds-lawns/ 

https://cmg.extension.colostate.edu/Gardennotes/552.pdf

No matter which herbicide product you choose, make sure to read the entire label and follow all directions for mixing and applications, including personal protective equipment. 

Here is another great resource about lawncare and management best practices:

http://extension.colostate.edu/topic-areas/yard-garden/lawn-care-7-202

I hope this helps,

Dawn